Evaluate : `intx^(n)logxdx`.

Explanation

(i) Integrating by parts, taking x as the first function, we get
`intx^(n)logx=(logx)*intx^(n)dx-int{(d)/(dx)(logx)*intx^(n)dx}dx`
`=(logx)*(x^(n+1))/((n+1))-int(1)/(x)*(x^(n+1))/((n+1))dx`
`=(x^(n+1)logx)/((n-1))-(1)/((n+1))intx^(n)dx`
`=(x^(n+1)logx)/((n-1))-(x^(n+1))/((n+1)^(2))+C`.